1. The Field of the Invention
The present invention relates to a magnetic data eraser that is configured to erase magnetic data stored in a magnetic recording medium such as a hard disk drive.
2. Description of the Prior Arts
Nowadays, when a magnetic disk drive (hereinafter, it is exemplified by a hard disk drive) is intended to be discarded after it has been finished to be used in an office of a company or by an individual person, magnetic data should be erased by formatting the hard disk drive, for example, upon a request from an operating system in a computer while the hard disk drive is connected to the computer, in order to conceal the magnetic data stored in the hard disk drive from a third person, i.e., an unrelated person.
However, in the above mentioned method, only a management region of the hard disk which manages arrangement of magnetic information on the hard disk and the like may be erased, and actual magnetic information is remained on the hard disk. Thus, for example, a method for erasing information stored in the magnetic disk drive has been accepted to be carried out with applying magnetic force generated by an electromagnet on the magnetic disk drive.
Japanese Laid-Open Patent Application 2007-66439 discloses an invention relating to a data eraser that performs data erasing process with a simple operation to prevent the magnetic data stored in the magnetic recording medium to be discarded from leaking, in particular discloses an invention relating to a data eraser that performs data erasing process by applying horizontal magnetic field from a magnet on the magnetic recording medium.
However, recently a perpendicular magnetic recording method becomes to be adopted, and in the perpendicular magnetic recording, magnetic field being in a perpendicular direction is applied to the magnetic disk drive to store data in the magnetic recording medium. This perpendicular magnetic recording method may be more effective in comparison with an in-plane magnetic recording method (or horizontal magnetic recording method) which is one of the conventional recording methods including one disclosed in Japanese Laid-Open Patent Application 2007-66439, because the perpendicular magnetic recording method can provide an improved recording density of data in comparison with the in-plane magnetic recording method. Hence, when data stored in the magnetic disk drive is intended to be erased, because the magnetic disk drive may utilize either the in-plane magnetic recording method or the perpendicular magnetic recording method and it cannot be determined which method is utilized only by looking its appearance, it has been needed to operate a data eraser to apply magnetic field being in the horizontal direction to the magnetic disk drive or to apply extremely strong magnetic field, and then further to apply magnetic field being in the perpendicular direction to the magnetic disk drive.
Therefore, there has been needed to take a longer time and complex operations to perform data erasing process for erasing date stored in a magnetic recording medium by using a conventional data eraser. Further, a large electric power has been needed to supply to an electromagnet to generate magnetic field to be used for applying to the magnetic recording medium.